In response to newly released health information during the past decade, the public has grown increasingly concerned about contaminants in tap water. Accordingly, there has been an increasing demand for purified water at home and at the work site.
Sources of purified water include bottled water, which typically is delivered regularly at the home or office, and which is generally used with a dispensing system. While bottled water is generally of fair quality, the ongoing costs of water portage are quite high. Also, customers of bottled water are often shocked to learn the contaminant level within the purchased water. Another source of purified water is obtained by filtering tap water. The long term cost of filtering systems is relatively low compared to bottled water, but filtered water quality is typically not high. Many contaminants are not readily removed by filtering. Water distillers for home and office use have been available for quite some time. Distillers are able to provide a water quality at least as high or better than bottled water, although distilled water costs significantly less than bottled water when costs are considered over the reasonable life of the distiller.
The water distillation process heats the water to produce steam, and then condenses the steam to form water free from those contaminants which have a vaporization temperature higher than water. Contaminants having a vaporization temperature lower than water are separated from the steam by venting prior and during the condensation operation. The purified water may then be filtered "polished", if desired. U.S. Pat. No. 4,894,123 disclosed a high efficiency distiller which utilizes a preheat chimney and a low wattage heating coil.
In spite of the many advancements that have been made over the years with home, office, or "end user" water distillers, significant problems still remain. These problems relate largely to the long term use of water distillation units, including ease of operation, long term monitoring of water quality, and automatic self-maintenance of the system in response to such monitoring.
Many prior art distillation units are difficult to clean. While the entire distillation and water storage system may be sterilized with steam, some components within the distiller cannot be intermittently subjected to high temperature steam, and must be removed from the assembly prior to sterilization. Prior art distillation units are typically unable to detect when water quality will drop below a desired level, and accordingly the entire distillation and water storage system becomes contaminated. Other units require the user to partially disassemble the assembly and periodically drain the water from the heater bowl into a pail or other receptacle. Many prior art distillation units are not user friendly, and do not provide the user with sufficient information to reliably operate and periodically clean the assembly.
For long term water quality, corrosion of the flow lines for both the steam and condensed water must be avoided. While stainless steel is used in better quality home distillers to avoid corrosion, corrosion remains a problem in components with welded seams, such as the distiller radiator used to cool the steam.
Some municipal or state agencies have enacted or proposed legislation which would prohibit the drainage of the contaminants remaining in the distiller heating bowl into the normal tap water drainage system. Such drainage may be prohibited even though these same contaminants were in the tap water prior to distillation.
Consequently, there remains a need for an end user water distiller that offers dependable operation for long term use with minimum maintenance. Those skilled in the art have long sought and will appreciate the present invention which provides solutions to these and other problems.